Pesticidal phosphorus esters



PESTICIDAL PlififilHURUS ESTERS Joe R. Willard and .i'ohn F. Henahan,Middleport, N."l., "assignors to Food Machinery and ChemicalCorporation, New York, N. Y., a corporation of Delaware No Drawing.Application July 16, 1956 Serial No. 597,386

3 Claims. a. ter -22 This invention relates to novel pesticidalcompositions, and particularly to compositions which are useful asinsecticides, acaricides and ovicides. More specifically, it has beendiscovered that compounds of the class of bis(S-(diallcoxyphosphinyl)mercapto)methanes andbis(S-(diallgoxyphosphinothioyl)mereapto)methanes p o s s e s suniquepesticidal activity, in that they function as effective activeingredients in insecticidal compositions, acaricidal compositions andovicidal compositions. The subject compounds have the general formulawherein X is oxygen or sulfur, R is hydrogen or an organic radical, andR, R R and R are organic radicals. Compounds of this general type havereportedly been prepared within the CHR- group in the foregoingstructural formula is derived from an aldehyde. It has now beendiscovered that a large variety of substituted methylene esters of thistype may be prepared from a methylene dihalide having the generalformula Y-CHR- Z wherein Y and Z may be chlorine or bromine. In additionto hydrogen, the R group of the dihalide may be av hydrocarbon radicalsuch as alkyl, aryl, cycloallryl, aralkyl, alkaryl and the like, or Rmay be a substituted hydrocarbon, containing groups such as chloro,bromo, nitro, alkoxy, hydroxy and the like, or R may be a functionalgroup such as carbalkoxy, carbamido, carbanilido,

halogen, alkoxy, nitro and the like. The use of the halide rather thanthe aldehyde greatly enlarges the number and types of substituents whichmay be represented by R.

The methylene dihalide is condensed with a metallic salt of a thioordithiophosphoric acid, of the formula,

In the preferred process of this invention, two molar equivalents of theappropriate phosphorothioic or phosphorodithioic acid is dissolved in asolvent such as ethanol or dioxane, and a solution of the metalhydroxide is added until the pH is about seven. A -40% solution y ofpotassium hydroxide in ethanol is a convenient reagent. A preformed saltof the phosphorus acid may also be used, dissolved in a solvent. lutionis added one molar equivalent of the desired meth- To the neutral.so.-

A. 2,873,228 Patented Feb. 10, 1959 ylene or substituted methylenedihalide, and the mixture is heated until the reaction is complete. Thisgenerally requires about 4-14 hours under reflux. The product isseparated and tested for pesticidal activity.

The following examples illustrate the preparation of typical compounds.There are of course many modifications of these techniques which may besuccessfully employed by those skilled in the art, and which do notdepart from the spirit and scope of the invention.

EXAMPLE 1 Bis(S-(diethoxyphosphinothioyl)merca pto)methane Two molarequivalents of 0,0-diethyl hydrogen phosphorodithioate were dissolved insuflicient ethanol to-give afour molar solution. 20% ethanoliepotassiumhydroxide was added slowly, the temperature maintained below 50 duringthe addition, until the pH of the solution was approximately 7.0. To theneutral molar equivalent of dibromomethane and the mixture was heatedunder reflux for six hours. The precipitated solid was isolated on afilter and the filtrate was concentrated under'vacuum. The residue afterremoving the solvent was diluted with ether, the solution washed withtwo volumes of water and the ethereal layer dried. The dried solutionwas concentrated under vacuum to give 0.74 molar equivalent of acolorless liquid having an n D ANGIYSZZSX-Cfikd. for C9H2204P2S4I P, S,33.34; P/S ratio, 0.50. Found: P, 16.04; S, 33.72; P/S ratio, 0.51..

When thedibromomethane in the above procedure was replacedbychlorobromomethane, 0.78 molar equivalent of colorless liquid having ann D 1.5285 was obtained. Bio-assay, and chemical analysis, indicated thetwo products to be identical. Analysis.-Calcd. for C H O P S P, 16.13;S, 33.34; P/S, 0.50. Found: P, 16.25; S, 33.63; F /S ratio, 0.50.

EXAMPLE 2 Bis(S- dicyclohexyloxyphosphinothioyl) mercapto) Two molarequivalents of 0,0-dicyclohexyl hydrogen phosphorodithioate wasneutralized by addition of 20% ethanolic potassium hydroxide, thetemperature maintained below 50 solution during the addition, and to theneutral wasadded one molar equivalent it dibromomethane. The mixture Washeated under reflux for 2.5 hours. and the reactionmixture treated asdescribed in Example 1 to give 040 molar equivalent of a viscousorange-brown liquidhaving an r1 1) 1.5290. Analysis.- Calcd. for C H O PS P, 10.32; S, 21.34; P/S ratio, 0.50. Found: P, 10.45; S, 2129; P/Sratio, 0.51.

EXAMPLE 3 (4-nz'trophenyl) -br's(S- (dietlzoxyphosphinoth ioylinercapt0)methane l 0 CaHs CaHa solution was added 1 Two molarequivalents of potassium 0,0-diethyl phosphorodithioate was reacted withone molar equivalent of 4-nitro-benzal chloride as described inExample 1. From the reaction mixture was obtained 0.52 molar equivalentof a red-orange liquid having an n D 1.5753. Analysis- Calcd. forC15H2506S4P2NI P, S, ratio, 0.50. Found: P, 12.20; S, 25.70; P/S, 0.49.

EXAMPLE 4 Bis(S-(diethoxyphosphinyl)mercapt)methane To an ethanolicsolution containing 2 molar equivalents of sodium0,0-diethylphosphorothiolate, prepared by reaction of elemental surfurwith 0,0-diethyl phosphite according to the procedure of Fiszer et a1.(Chem. Abstracts 49, 3786 (1955)), was added one molar equivalent ofdibromomethane. The reaction mixture was heated under reflux for sixhours and the product recovered as described in Example 1, to give 0.23molar equivtions, or in any other suitable vehicle.

30 (Kltb.)

The compounds of this invention were evaluated for pesticidal activity.It was found that all were not equivalent in activity, but that somewere superior as insecticides, some as acaricides and some as ovicides,and that some showed systemic activity as well. Some of the compounds inthis group showed an unusually broad range of activity characterized byhigh toxicity.

The pesticidal compositions may be formulated as aqueous emulsions, asdry or wettable powders, as solu- The compositions can be utilized assprays, as dusts, as aerosol mixtures, insecticidal coatingcompositions, and as residues. In general, they can be applied bymethods commonly used for control or eradication of insects, mites andthe like. Thus, these compositions may be formulated with solvents,diluents, and carrier media, adhesives, spreading, wetting andemulsifying agents and other ingredients.

A typical formulation used in evaluating the toxicants of this inventionis a wettable powder containing 25% of the candidate pesticide, 72%Attaclay (fullers earth) and 3% of an alkyl aryl polyether alcohol aswetting agent. This wettable powder is applied to plant foliage as anaqueous suspension, by spraying. The treated plants are infested andobservations made at intervals to determine the efiicacy of thecompounds as toxicants.

Insects used in the testing included the German roach (Blattelagermanicw (L.) Mexican bean beetle (Epilachnia varivestis Mu1s.),southern armyworm (Prodem'a eridwnia (Cram.)), pea aphid (Macrosiphumpisi confused flour beetle (Tribolium confusum Duv.) and twospotted mite(Tetranychus bimaculatus Harvey).

TABLE 1. PHOSPHINOTHIOYL- AND PHOSPHINYLMEROAPTO- METHANES a rR'O-P-S-CHz-S-P-0R' Compound Analysis msD R R X Theory Found S 1. 5247P-18. 89 P-17. 39 S 1. 5315 P-16. l3 P-16. 04 0 1. 4678 P17. 58 P-19.S 1. 5220 P-l4. 08 P-14. 04 S 1. 5163 P-14. 08 P-14. 06 n-Butyl- S 1.5110 P-12. 49 P-12. 18 Isobutyl Isobutyl 8 1.5088 P12.40 P-12. 18Ethyl/lsopropyl (1:1). Ethyll/lsopropyl S 1. 5258 P-15.04 P-15. 09Ethyl/isopropyl (3:1) Ethylgl isupropyl 1. 5298 P15. 57 P-15. 60Oyelohexyl s 1. 5290 P10.32 P10.49 Phenyl S 1. 6722 P-10. 74 P-10. 83p-Chl0rophenyl S 1. 5805 P- 8.87 P- 8. 51 Phenyl S 1. 5350 P-12. 87P-12. 47

TABLE 2.-SUBSTITUTED PHOBPHINOTHIOYL- AND PHOSPHINYLMEROAPTOMETHANESCompound Analysis nuD R 1 R 1 R X Theory Found Ethyl Ethyl Phenyl S 1.5497 P17.47 P12. 91

Do .do do 0 1. 5170 Phenyl Pheny do 8 1. 5853 P 9. 66 P-10. 204-Chlorophenyl -Chlorophenyl-.. --.do S 1. 5630 P 7.04 P- 8.08 EthylEthyl 2, 6-DichlorophenyL S 1. 5712 P11.70 P11.95 d 4'Nltrophenyl S 1.5753 P12. 25 P-12.20 (1 .do 0 1. 5352 S13. 55 S- 12. 95

Carbethoxy S 1. 5123 N, N-Dlethyl- S 1. 5078 P-l2. 87 P12. 51

carbamido. N -Phenyl- 1, 5532 carbamldo.

+3 6 Table 3 below represents the results of screening tests Pursuant tothe requirements of the patent statutes, the of variousbis(S-(dialkoxyphosphinothioyl)mercapto) principle of this invention hasbeen explained and exempliniethanes. Anumber of these compoundsexhibited residfied in a manner so that it canbe readily practiced byual, slow acting or ovicidal activity against two-spotted those skilledin the art, such exemplification including mites, and residual activityagainst Mexican bean beetles 5 What is considered to represent the best.embodiment of and pea aphids. A plus sign in Table 3 indicates theinvention. However, it should be clearly understood significantoviciclal activity. that, within the scope of the appended claims, theinven- TABLE 3,-INITIAL CONTACT ACTIVITY OFBIS(S-(DIALKOXYPlIOSPHINOTHIO YL)MERCAPTO)METHANES r RO-IP-S---CH-S-lF--OR OR2 OR2 n.

Gompound 1! Percent Kill at 1,250 p. p. m. ---i- V I Two-spotted MitesMexican Southern R R 2 R in German Bean Army- Pea Roach Beetle wormAphid Adults Nymphs Ova I i s 96 75 0 0 0 1mm 5 t 100 100 100 100 100 0100 100 100 100 5 100 r s 95 90 0 50 100 65 j yl s 100 100 0 on 0 0 I s100 100 0 100 0 0 Ethvl s 100 100 90 100 n is s 100 100 100 100 100 s100 100 0 100 15 i 0 v s m 95 i Q 0 0 e0 0 s 100 100 100 i 100 too I s100 100 I 55 10 i To measure ovicidal activity, horticultural beanplants tion may be practiced by those skilled in the art, and hay wereinfested with adult two-spotted mites. A period of ing the benefit ofthis disclosure, otherwise than as specififour to five hours was allowedfor the deposition of eggs. cally described and exemplified herein. Theovicidal materials were then applied to the eggs by That which isclaimed as patentably novel is: dipping the leaves into aqueoussuspensions of Wettable 1. A pesticidal composition comprising as anessential powder formulations of these materials one and three daysactive ingredient a toxic concentration of the compound afterinfestation. Ovicidal activity against Mexican bean bis(S[diethoxyphosphinothioyl]mercapto)methane of beetle ova was measured bydipping one-day-old egg the formula masses in an aqueous suspension of awettable powder formulation of the test material and maintaining the wet5 egg masses at room temperature for 6 days.

Test results are shown in Table 4, for ovicidal activity of bis(S(diethoxyphosphinothioyl)mercapto)methane 002m CEHE against Mexican beanbeetle and two-spotted mite eggs. TABLE 4.-OVICIDAL ACTIVITY ornrssmn'rnoxy and an inert pesticidal adjuvant as carrier therefor.

PHOSPHINOTHIOYL)MERCAPTQMETHANE 2. A method for controlllng ante andinsect pests and ova which comprises contacting said pests and ova withan eifective concentration of the compound bis(S-[dit 1 Ova eoi iigti mBehavwl 0mm 0 (g5 ethoxyphosphinothloyl]mercapto)methane.

3. B1s(S [dlethoxyphosphmothioyl]mercapto)methane, having the formula1,250 Deteriorated without atching. Mexican Bean Beetle (treated 39Hatched, all larva died 021150 5 S 00235 one-dey-old). instantly. H

0 Hatched, larva normal. 5 P S CHPS P 156 0% hatched. g3 CaHsO O CzHsTwo-spotted Mite (treated 20 8% hathem 1o 42% hatched.

5 100% hatched' References Cited in the file of this patent 1 0%1 1atched.

0. 39 Do. UNITED STATES PATENTS Two'spotted Mite (treated 20 2% hatched.

mmld) g i315; ggtg'ggg; 2,266,514 Romieux et a1. Dec. 16,1941 0 98%hatched- 2,596,076 Hook et al. May 6, 1952 2,736,737 Morris Feb. 28,1956 UNITED STATES PATENT OFFICE Certificate of Correction Patent N 0.2,873,228 February 10, 1959 Joe R. Willard et a1.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 1, lines 25 to 28, the formula should appear as shown belowinstead of as in the patent column 3, line 18, for surfur read--sulfur-; columns 3 and 4, Table 1, the formula should appear as shownbelow instead of as in the patentx R'OI -SCHn-S-i -OR' OR? B2 samecolumns 3 and 4, Table 2, first column thereof, in the heading, for Rread -R.

Signed and sealed this 7th day of July 1959.

Attest: KARL H. AXLINE, ROBERT C. WATSON, Attestz'ng Oficer.Oomz'ssz'oner of Patents.

2. A METHOD FOR CONTROLLING MITE AND INSECT PESTS AND OVA WHICHCOMPRISES CONTACTING SAID PESTS AND OVA WITH AN EFFECTIVE CONCENTRATIONOF THE COMPOUND BIS(S-(DIETHOXYPHOSPHINOTHIOYL)METHANE.
 3. BIS(S -(DIETHOXPHOSPHINOTHIOYL)MERCAPTO)METHANE, HAVING THE FORMULA